Spoff (boffin, swat etc)- a derogitory term that people (midlands, england) use for others more intelligent than themselves. A spoff is suposed to be the one who asks for extra homework and revises for 2 hours for a maths quiz, however, many people innocent of spoffiness are accused of this merely because they are naturally intelligent.

kid one - what did you get?
kid two - 9 out o 10, you?
kid one -oh my god, you SPOFF! i got 3 (smiles with a pride that they underacheived, as it is 'cool')